A vehicle air conditioning system conventionally includes a compressor, a condenser, an evaporator, and an accumulator arranged as a refrigerant circuit. The compressor compresses the refrigerant for delivery to the condenser, where the state of the refrigerant changes from gaseous to liquid. The liquid refrigerant then passes to the evaporator, where an air blower circulates air over the evaporator to the vehicle passenger compartment. The resulting heat transfer from the ambient air to the evaporator causes the refrigerant to mostly change state from a liquid back to a gas.
Liquid and gaseous refrigerant then pass from the evaporator to the accumulator. The accumulator separates the liquid refrigerant from the gaseous refrigerant, allowing only gaseous refrigerant to return to the compressor. The residual liquid refrigerant eventually turns to a gaseous state and is then returned to the compressor. The accumulator also provides for recovery of lubricating oil contained in the refrigerant, and for returning a metered amount of the oil to the inlet side of the compressor.
The accumulator normally is an upright cylindrical housing with an inlet opening formed therein and an outlet tube having its mouth in the upper interior region of the accumulator. Refrigerant from the evaporator is introduced into the accumulator through the inlet opening, which may be in the top or in the side of the accumulator housing. The liquid refrigerant settles to the bottom of the accumulator. Gaseous refrigerant rises to the top of the accumulator, where suction created by the compressor draws the gaseous refrigerant through the outlet tube.
To prevent any liquid refrigerant from passing directly from the inlet opening into the mouth of the outlet tube and being drawn back into the compressor, some structure is typically provided to act as an outlet tube shield. The shield is conventionally either a domed or frustoconical shape.
An example of the domed construction appears in U.S. Pat. No. 4,474,035 to Amin et al., assigned to the assignee of the present invention. Amin et al. discloses an accumulator including a domed baffle plate adjacent the accumulator inlet opening. Liquid portions of the refrigerant are disbursed onto the domed baffle plate and down the sides of the accumulator, allowing the gaseous components of the refrigerant to accumulate in the upper regions of the accumulator adjacent the mouth of the outlet tube. The baffle is spot-welded to the inner wall of the accumulator.
Examples of the frustoconical type shield include U.S. Pat. No. 4,270,934 to Widdowson et al. Widdowson et al. discloses an integrally molded baffle that is supported in the interior of the accumulator on the open upper end of the outlet tube, rather than spot welded to the housing of the accumulator. U.S. Pat. No. 4,291,548 to Livesay discloses an accumulator having a baffle of truncated conical shape. The baffle is subassembled with the outlet tube, and then secured as a unit in the accumulator casing at a single joint with an upper casing portion prior to joining with a lower casing portion. U.S. Pat. No. 4,675,971 to Masserang similarly discloses a baffle which is fit onto the upper end of the outlet tube before those components are put into the accumulator.
A problem with the use of domed or frustoconical outlet shields is that they must be separately formed, and then secured within the interior of the accumulator housing. As described, the shield may be secured by spot-welding or some other means, but the requirement of separate parts to complete the accumulator assembly remains. Consequently, complexity of the accumulator and the time necessary to assemble it are relatively great.